connectors in a signal path

[Brian Roth]

I decided to branch off from this thread:

https://groupdiy.com/threads/xlr-grounding.84011/page-2
In a perfect world (lol) a signal from a mic in a studio or live system would consist of NOTHING but a cable hard-soldered to the mic's internal element that is also hard-wired directly into the input transformer/transistors of the preamp. No connectors.

(sidebar..... I am NOT going down a rabbit hole re. "damn...this brand of solder or cable totally destroys the sound from the mic.")

In the real world, we have to use connectors. IMHO, XLRs are our best choice for low signal levels. After decades working with this, TT bays (even from reputable companies like Switchcraft, ADC, etc) are totally unreliable for mic levels.

Besides XLRs I have decent experiences with EDAC/Elco multipin connectors.


Ahhhh yes....let the flame wars begin....lol.

Bri

 

[soapfoot]

We just ditched the TT bays in our mix room in favor of Flock digitally-controlled relay-based systems

Can’t say I’ve noticed (nor listened for) an improvement in sound, but it’s sure nice to not have to chase down bad patches, and it’s even nicer to not have to unplug a zillion cables at the end of the day

 

[ruffrecords]

We just ditched the TT bays in our mix room in favor of Flock digitally-controlled relay-based systems

Can’t say I’ve noticed (nor listened for) an improvement in sound, but it’s sure nice to not have to chase down bad patches, and it’s even nicer to not have to unplug a zillion cables at the end of the day

Can they route any line to any line or are there limitations? I notice their 16x16 matrix has 256 relays in it.

Cheers

Ian

 

[Newmarket]

After decades working with this, TT bays (even from reputable companies like Switchcraft, ADC, etc) are totally unreliable for mic levels.

Any view on Mosses & Mitchell Bantam patchbays ?

 

[Brian Roth]

Any view on Mosses & Mitchell Bantam patchbays ?

Is those used in Trident 80B/C and TSM desks?

Bri

 

[Newmarket]

Is those used in Trident 80B/C and TSM desks?

Bri

I don't know tbh. Many years ago I worked at Penny & Giles. They sold them. And I have one because it had minor damage (non - electrical) but have never used it. But I don't recall any problems being reported. Of course there are two elements. The patchbay itself then the condition of the cable and connectors. They are space efficient but the B guage Jacks have the edge wrt surface contact area.

 

[kags]

Any view on Mosses & Mitchell Bantam patchbays ?

MM patchbays are extremely reliable. We have three rooms with 96 channel consoles (over 1k patchpoints per room) and we've had one or two connectors come loose inside the panels from abuse, but not one connection is flaky or intermittent in the bay. We do burnish our bays every few years if we notice connections that need a twist to make good contact. I highly recommend these bay. The older switchcraft bays are very reliable, as well.

 

[pucho812]

We just ditched the TT bays in our mix room in favor of Flock digitally-controlled relay-based systems

Can’t say I’ve noticed (nor listened for) an improvement in sound, but it’s sure nice to not have to chase down bad patches, and it’s even nicer to not have to unplug a zillion cables at the end of the day

The guy from orphan audio says that the flock patchbays have a low headroom and that your line signals can distort. Is this the case?

In the past Walter sear and others did the math and figured a standard tt bay has a headroom too but it’s well beyond something like +50dBu

 

[soapfoot]

Can they route any line to any line or are there limitations? I notice their 16x16 matrix has 256 relays in it.

Cheers

Ian

Any line to any line, but only within one unit.

We have one of the 16x16 units and also one of the larger 96x96 units (patch XT).

The smaller unit handles our multibus processing (stereo gear for buses), and the XT handles all of our inserts.

The one downside is that the gear in each has to stay in its own ecosystem… I can’t decide that I want to use one of the bus compressors as an insert on a pair of tracks (like I used to with the TT bays).

But we have a pretty considerable amount of outboard gear. A more modest setup could likely do it all within one unit.

The software interface is pretty cool.

I can just drag gear onto an insert, change the order, put any chain together… and it all just clicks into place instantaneously and without thinking about it or leaving the chair (or the sweet spot)

 

[totoxraymond]

Hi,

Does anyone have some experience with ghielemtti patchbays for microphones? It shouldn't have the limitations of bantham regarding patching with phantom power on while having the same number of connections per rack unit.

Thomas

 

[sodderboy]

I have never had any design or functional issues with patchbays for microphone level. Very rarely have I ever had to clean normals or isolate mic line problems to any kind of TTY patchbay. The best thing to do is train the client to keep them vacced with a good brush. I can test the sleeves for cleanliness and every 5-7 years-ish might want to gently clean/condition internal contacts. Search "burnisher" on groupdiy is all I'll say about that.

The Flock is a great concept, but I wonder if as a one-time booking client I could mult a mic in order to use my portable TransAmp DIY pre on a tie panel in a record chain and steal P48 for the mic from a console pre? Takes a matter of seconds with TTY.

Mosses & Mitchell patchpoints- on an SSL X000 series they are tanks, you just have to keep on top of loose patchpoints. M&M on those Trident vertical cards were OK until the sleeve breaks from the frame, they do not hold a cord, and the points are no longer made. M&M dsub bays are bad in my experience. They come standard with SSL Duality installs and they always have dodgy ribboning inside where half of a normal is missing. I always test them now for resistance through before connecting because they are not shipped QC sampled 100%, and I have to re-link a few connections inside a bay or two in an install.
For hard-wired I only use Audio Accessories, and although I like their 1U dsub bays, the lead time is usually such that I will get the bays in-hand months after a job is to be finished.
When I re-do a NEVE bay I swap the Switchcraft for AA points.
When I first used a TAC Scorpion I thought the plastic points were a joke that would keep us employed fixing them. They have been surprisingly robust.
That said I use the REDCO dsub or EDAC bays exclusively for designs. Small setups are subject to change often and the installations using them hold their value compared to a hard-wired install. I took a chance with the "plastic points" almost 20 years ago and have been more than satisfied to this day. They take heavy daily wear abuse. Again, keeping ANY bay dust/dirt-free is a must. Yes, slam a chair against cords patched in and you will break them, but placing them properly is part of a good system design in the first place. I have had to replace one REDCO bay in a studio where more booze soaks into the eqpt than the clients. It had a crazy oscillation blowing Bryston channels, and finally solved it by replacing with a used 10+ year old bay from a different room being upgraded. I never had any dropped internal connections compared to the M&M's.
The Neutrik dsub bays look robust, but their programming is just TMI. You have to dismantle the bay block-by-block to program it. They have metal sleeves on them, but they are not connected to the point's shield contact/dsub pin. Why bother? It's just for show, really, so they are just as plastic fantastic as the TAC style points.
Multipair connections, I prefer EDAC but Homey don' play dat in the SSL world. Like so many things in life, the responsibility factor with DL connectors is not on the DL connector but on the person using it. The same person who bends a DL pin will probably jam an EDAC just as easily.
Cinch-Jones, Winchester, Plessey (bleccch!) I would not consider in new installations but will deal with what I have to on vintage eqpt.
Mike

 

[Matt Syson]

M+M and Switchcraft longframe TT jacks are good especially if mounted the right way up and kept free of dust, drinks and bodily fluids. PCB mounted versions must have extra support and not rely on soldered connection points alone. Some of these details can be quite subtle but give different experiences with reliability. Using the correct metal for the spring contacts and getting the shape of them correct is important, and there are dodgy patch cords around that if you just 'ram them in' can damage spring contacts that are not suited to the tip size/shape of some plugs. 'Big name' companies that have taken over 'cheap' brands without ensuring proper quality can also be a problem.

 

[nsalis]

We just ditched the TT bays in our mix room in favor of Flock digitally-controlled relay-based systems

Can’t say I’ve noticed (nor listened for) an improvement in sound, but it’s sure nice to not have to chase down bad patches, and it’s even nicer to not have to unplug a zillion cables at the end of the day

The "Flock PATCH Series digitally controlled analog audio routing systems" (as they call it) is not relay-based. They use a semiconductor crosspoint switch array as the switching element. This switches unbalanced audio signals so that buffer amplifiers with balanced inputs or outputs are connected before and after the array. Even though the quality of these circuits may be high, there is active electronics in the signal path. In this respect, the system is not directly comparable to a passive patch bay system. The system is intended for switching line-level signals. I have attached the specs I received from Flock.

 

[nsalis]

Hi,

Does anyone have some experience with ghielemtti patchbays for microphones? It shouldn't have the limitations of bantham regarding patching with phantom power on while having the same number of connections per rack unit.

Thomas

 

[nsalis]

Although we and our projects are mostly in Switzerland (like the Ghielmetti company) I didn't specify them. The reason was the extremely high prices, which were probably related to the fact that the taxpayer-financed public broadcasters, theatres and opera houses, for whom costs are irrelevant, installed these panels en masse. I don't know what the current price situation is.

In terms of quality, I've only ever heard good things about the panels from the broadcaster's studio engineers. They are extremely reliable, corrosion-free and have high crosstalk between channels. Ghielmetti's homepage is not very enlightening. A better overview can be found on the Canford website:

https://www.canford.co.uk/GHIELMETTI-DIGITAL-ANALOGUE-PATCH-PANELS
or

https://tinyurl.com/3fybdn3k
Nick Salis

 

[nsalis]

Correction, should have read: "... have high crosstalk attenuation between channels".

Nick Salis

 

[nsalis]

I have never had any design or functional issues with patchbays for microphone level.

I never voluntarily had classic patch panels (patch bays) in our projects to route microphone levels. I was afraid that the relatively small voltages and the sparking when applying the phantom DC voltage could lead to transmission problems and premature wear. However, we had a customer, the A/V manager of a very large company with many auditoriums and studios, who came from the broadcast scene and insisted that we also use patch panels for microphone levels. He also wanted the 4.4mm ("Bantam" style), not the Longframe (6.3mm) in his systems. Ultimately, the customer pays and commands, and having acknowledged my concerns, we specified a number of bantam patch panels for microphone signals.

The oldest system is still running today, it's been 22 years since it was set up.

We don't experience any problems with oxidation or other contact problems. The panels are not specifically maintained, but repatching is done relatively frequently, and the control room is air-conditioned to a high standard, has no dirty outside air and smoking is prohibited.

The supplier was company Audio Accessories, Inc.,

http://www.patchbays.com/
which had also been manufacturing pre-wired long-frame line-level patch panels for us for a long time. For mic patching they recommended a so-called "Sleeve Normal" patch bay.

I have added an English translation to my original note about these panels and enclose them here.

I don't want to doubt that in less well-maintained surroundings XLR patch panels are less delicate than open patch bay jacks with switching contacts.


Nick Salis

 

[nsalis]

In the past Walter sear and others did the math and figured a standard tt bay has a headroom too but it’s well beyond something like +50dBu

I wouldn't speak of headroom here. But of course not arbitrarily high voltages and currents can be sent via the delicate contacts of the patchfield jack. For example, the Switchcraft Longframe and Bantam Jacks have an allowable working voltage of 140 VDC and a maximum allowable current of 0.1 A. That would correspond to a maximum 50 volt sinusoidal audio signal, which is 36 dBu. If you then subtract the usual 20 dB of headroom, you end up with a maximum nominal level (0 VU) of 16 dBu.

Nick Salis

 

[nsalis]

The guy from orphan audio says that the flock patchbays have a low headroom and that your line signals can distort. Is this the case?

The specification I received from Flock indicated a maximum undistorted level of 28 dBu. Since they didn't differentiate between input and output levels, I assume this value applies to both. So, assuming you're working at a nominal studio level of 0VU = 4dBu, you would have (28 - 4 =) 24dB of headroom, which is reasonable.

Nick Salis

 

[pucho812]

I wouldn't speak of headroom here. But of course not arbitrarily high voltages and currents can be sent via the delicate contacts of the patchfield jack. For example, the Switchcraft Longframe and Bantam Jacks have an allowable working voltage of 140 VDC and a maximum allowable current of 0.1 A. That would correspond to a maximum 50 volt sinusoidal audio signal, which is 36 dBu. If you then subtract the usual 20 dB of headroom, you end up with a maximum nominal level (0 VU) of 16 dBu.

Nick Salis

I can push over 30dBu through a tt bay without issue regardless of brand.